Development of a new amperometric biosensor based on polyphenoloxidase
and polyethersulphone membrane*
P. V. Climent1, M. L. M. Serralheiro2, and M. J. F. Rebelo1,**
1CECUL, 2CCMM, Faculdade de Ciências da Universidade
de Lisboa, Campo Grande, C 8, 1749-016 Lisboa, Portugal
Abstract: An amperometric biosensor based on the enzyme polyphenoloxidase
(PPO), which makes the bioelectrocatalysis of phenolic compounds, was
developed and optimized using cathecol as substrate. Polyethersulphone
membranes were used for enzyme immobilization. Polyphenoloxidase oxidizes
monophenols (cresolase activity) and diphenols (catecholase activity)
into the corresponding o-quinones; the o-quinones formed in the enzymatic
catalysis are then reduced back to cathecol at 200 mV (vs. Ag,
AgCl) at a platinum electrode. The polyphenoloxidase immobilized was
from commercial origin or extracted from mushrooms. p-Cresol and phenol
substrates were also tested. Reproducibility, response time, linearity,
sensitivity, and stability of the biosensor were studied.
* An issue of reviews and research papers based on
presentations made at the IUPAC/ICSU Workshop on
Electrochemistry and Interfacial Chemistry in Environmental Clean-up
and Green Chemical Processes, Coimbra, Portugal, 6-7 April, 2001.
** Corresponding author.
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